Project SEE (Satellite Energy Exchange) is an international effort todevelop a space-based mission for precise measurements of gravitation.Gravity is the missing link in unification theory. Because of the uniquepaucity of knowledge about this, the weakest of all known forces, andbecausegravity must have a key role in any unification theory, many aspects ofgravity need to be understood in greater depth. A SEE mission wouldextendour knowledge of a number of gravitational parameters and effects, whichare needed to test unification theories and various modern theories ofgravity.SEE is a comprehensive gravitation experiment. A SEE mission would testfor violations of the equivalence principle (EP), both byinverse-square-law (ISL) violations and by composition dependence (CD),both at ranges ofthe order of metres and at ranges on the order of RE. A SEEmissionwould also determine the gravitational constant G, test for timevariation of G, and possibly test forpost-Einsteinian orbital resonances. The potential finding of a non-zerotimevariation of G is perhaps the most important aspect of SEE. A SEEmission will also involve a search for new particles with very lowmasses,since any evidence of violations of the EP would be analysed in terms of aputative new Yukawa-like particle.Thus, SEE does not merely test for violations of general relativity (GR);SEE is a next-generation gravity mission.